I am having exactly the same problem. These used to work before I upgraded to 9.10. Now, the only way I can get wifi to work is if I click on the network manager applet in gnome and like you i wont be able to connect remotely to my office if my PC is somehow rebooted while I am away.
In my case, I have already tried manually editing /etc/network/interfaces, so I thought I must have done something wrong. So I install network-admin and configured wireless via that. The configuration that was added via the gui tool was:
iface wlan0 inet dhcp
When I tried rebooting and logging in via a text console, the interface did not come back up. dmesg showed me this:
[ 24.863155] ADDRCONF(NETDEV_UP): wlan0: link is not ready
I am pretty convinced there is some script that is failing to configure the interface properly before dhclient runs.
Please let me know if you found the solution to this problem. I have been searching the internet for some information for quite some time now and it has been frustrating.